Chinese Study: “Women With a Previous Induced Abortion Had a Significant Increased Risk of Breast Cancer”

The Coalition on Abortion/Breast Cancer notes that a Chinese study consisting of 1,351 subjects published in the Asian Pacific Journal of Cancer Prevention in February, 2012 reported a very statistically significant increased risk of breast cancer for women with previous induced abortions (IAs) in comparison with women without previous IAs. [1]Researchers led by Ai-Ren Jiang reported a statistically significant 1.52-fold elevation in risk for women with IAs and a “significant dose-response relationship between (the risk) for breast cancer and number of (IAs),” meaning that risk climbed with number of IAs.

For premenopausal women with IAs, the numbers were relatively small, and the observed 16% risk elevation was not statistically significant. However, for those with three or more IAs, the risk climbed to a statistically significant 1.55-fold elevation.

By contrast, postmenopausal women with IAs experienced a statistically significant 1.82-fold elevation in risk, compared to those with no IAs. Risk climbed with number of IAs from a statistically significant 1.79-fold increased risk for one IA and a statistically significant 1.85-fold elevation for two IAs, to a non-statistically significant 2.14-fold elevated risk for three or more IAs.

Professor Joel Brind (Baruch College, City University of New York) advised the Coalition on Abortion/Breast Cancer that earlier Chinese studies [3,4] underestimated the breast cancer risk of IAs. A one-child-per-couple policy is in force, and most women have abortions after first full term pregnancy. (First full-term pregnancy reduces risk by maturing 85% of the mother’s cancer-susceptible breast lobules into permanently cancer-resistant lobules.) He said it:

“tends to suppress the relative risk values, which makes the Jiang numbers all the more credible - underestimates if anything. Also, a place like China is good to measure the dose effect of abortion, and the statistics are strong enough to show a highly significant trend, which strengthens a causal inference.”

A Chinese study in 1995 by L. Bu and colleagues, including Janet Daling of the Fred Hutchinson Cancer Research Center, reported a statistically significant 4.5-fold elevated risk among women with IAs who developed breast cancer at or before age 35, compared to older women (who experienced a statistically significant 2.5-fold elevated risk). [2]

The Coalition on Abortion/Breast Cancer is an international women’s organization founded to protect the health and save the lives of women by educating and providing information on abortion as a risk factor for breast cancer.